Their definition doesn't matter. We're not going to hunt humans no matter how crazy they are and what they think they are or even if we played along to some degree in their desire to be treated like animals.

The view would make a little more sense if he said, "If they want to be treated like animals, then they should want to be hunted". Even if that were true, there is just no connection between "they should want to be hunted" and "they want to be hunted" and no connection between "they want to be hunted" and "We should hunt them".

Animals don't even want to be hunted, so it just makes no sense during any of the logical steps.

"If they want to be treated like animals" doesn't mean "We should treat them like animals" let alone "treat them like animals in every regard including hunting".